Vapor electric device



Oct. 12, 1937.

L. R. LU DWlG VAPOR ELECTRIC DEVICE Filed Nov. 11, 1953 INVENTOR lean E 1 00 1 19 WITNESSES: 54.7% a.

ATTORNEY Patented Oct. 12, 1937 UNITED STATES 2,095,756 VAPOR ELECTRIC DEVICE Leon R. Ludwig, Forest Hills, Pa., assignor' to Westinghouse Electric & Manufacturing Com.- pany, East Pittsburgh, Pa., a, corporation of Pennsylvania Application November 11, 1933, Serial No. 697,689

3 Claims. (01. 250-275) My invention relates to a vapor electric device and particularly to a cathode construction for a make-alive type converter.

The engineers employed in constructing and designing vapor electric converters have long realized that certain advantages could beobtained by operating a simple rectifier having the anode directly exposed to the cathode and closely spaced with regard thereto. However, until the invention of the make-alive type of exciter there were many practical reasons preventingthe satisfactory operation of such a simple converter. In the operation of simple converters of the make-alive type, it has been found that excess vapor pressure in the converter sometimes leads to unsatisfactory operation.

It is an object of my invention to provide a cathode construction for such'aconverter that willgreatly reduce the danger of failure of valve action.

It is a further object of my invention to provide a converter construction having a reduced arc drop and low energy loss.

In the converter, according to my invention, 25 the cathode is provided with a spot fixing body partially immersed in the cathode material and the make-alive electrode is so positioned that the cathode spot is initiated directly on the spot fixing body, preferably at 'the junction of the 30 spot fixing body with the cathode material. If this cathode andspot fixing body are suitably cooled, the resulting vapor pressure in the converter will be greatly reduced.

In practice it has been found that when an 35 arc plays directly to a mercury surface there is a blast of high velocity vapor produced whether by electrical or mechanical action is as yet unknown. However, by fixing the cathode spot on a spot fixing body this direct vapor blast is substantially avoided. Tests have indicated that this direct blast impinging on the exposed anode greatly reduces the reliability of the valve action of the converter.

It is accordingly an object of my invention to prevent a direct vapor blast in the converter.

Tests with a converter provided with the cathode according to my invention disclosed an unexpectedly low arc drop, said are drop being 5 of the order of six to eight volts with a consequent reduction of energy loss in the device.

Other objects and advantages of my invention will be apparent from the following detailed description taken in conjunction with the accompanying drawing, in which Figure 1 is a sectional elevation of a converter embodying my invention, and

Fig. 2 is a sectional view of the cathode of my improved converter taken along line IIII of Fig. 1.

The apparatus, according to my invention comprises a simple rectifier having a cathode l of mercury or other suitable vaporizable material and an anode 2 directly exposed to the cathode I and separated therefrom by a suitable insulator 3. A suitable make-alive electrode 5 having a tip of resistance material which extends into the converter and makes contact preferably by immersing a portion of the tip of the make-alive electrode 5 in the material of the cathode I.

A suitable spot fixing body such as the molyb denum covered coil 6 is partially immersed in the cathode material. This spot fixing coil 6 is so positioned that a portion of the coil is in contact with the make-alive electrode 5 in such manner that the make-alive electrode 5, the spot fixing body 6 and the surface of the cathode material I meet at a common point. 7

In order to insure that the cathode spot will be struck on the spot fixing body 8 preferably at the junction of-the spot fixing body 6 with the surface of the cathode I, Iprovide an insulating coating 8 such as glass on the major portion of the make-alive electrode 5, however, providing a small opening 9 in the insulating covering 8 permitting contact'between the spot fixing body 6 and the electrode 5 at the surface of the cathode material I.

In the operation of my converter, the application of ignition potential to the make-alive electrode 5 produces a cathode spot directly on the spot fixing body 6 at thejunction of the spot fixing body 6 with the cathode material I. When the main arc strikes to this cathode spot, it will spread directly along the spot fixing body 6 and will not wander over the surface of the cathode material.

In .order to further reduce the material evaporated from thecathodathe cathode I is thoroughly cooled, preferably by circulating a cooling fluid through the spot fixing body 6. In any event, it is desirable that both the cathode material and the spot fixing body 6 be thoroughly cooled when my converter is in operation.

While I have shown and described a specific embodiment of my invention, it will be ap parent to those skilled in the art that many changes and modifications can be made therein without departing from the true spirit of my invention or the scope of the accompanying claims.

I claim as my invention:

1. A vapor-electric device comprising an evacuated container, a pool type cathode therein, a main anode cooperating with said cathode, a make-alive electrode having a tip of resistance material dipping into said pool type cathode during normal operation of the device, a spot fixing body partially immersed in said cathode, said make-alive electrode and said'spot fixing body having a point of common contact with each other and the surface of the cathode and an insulating covering on the remainder of the surface of the tip of the make-alive electrode.

2. A vapor-electric device comprising an evacuated container, a pool type cathode therein, a main anode cooperating with said cathode, a make-alive electrode having a tip of resistance material dipping into said pool type cathode during normal operation of the device, a

a make-alive electrode having a tip of resistance material dipping into said pool type cathode during normal operation of the device, a spot fixing body partially immersed in said cathode,

'said make-alive electrode and said spot fixing body having a point of common contact with each other and the surface of the cathode and a vitreous covering on the remainder of the surface of the tip of the make-alive electrode.

LEON R. LUDWIG. 

